For instance, drawbar steered floor conveyors are realised such that one single driving wheel is mounted in a bearing around a horizontal axis in a bolster, and the bolster in its part is pivotally suspended around a vertical axis in the frame of the floor conveyor. The bolster supports also a driving motor for the steered wheel, which is in effective connection with the driving wheel via a gear. Thus, by pivoting the drawbar, an angular shift of the driving wheel and by that a steering action takes place. Usually, the control of the driving motor takes place via control elements on the head of the drawbar. It is not necessary to say that another control arm for the steering operation of the steered wheel can be provided too.
It is also known to provide a servo drive for the steering. For this purpose, a steering motor is used, which is fixedly attached on the frame and acts on a gearwheel which is arranged concentrically to the driving motor, via a chain for instance, in order to pivot the bolster or the driving unit, respectively. It is also known to fix a drawbar at another position of the vehicle frame, pivotally mounted around a vertical axis, without mechanical connection to the steered wheel. The steering angle is taken up by a sensor, which is shifted upon a pivotal movement of the drawbar. This signal is input as a desired value into a control equipment. A second sensor detects the steering angle of the steered wheel and transmits this value as a real value to the control equipment. With the aid of a suitable algorithm, real value and desired value are compared in the control equipment and a current is provided for the servo drive, so that the real value comes closer to the desired value. When the values are equal, the servo drive is switched off.
The present invention is based on the objective to provide a compact drive and steering equipment for drawbar-guided floor conveyors, which is realised with particularly little expenditure. In addition, it should have the property that it can readily replace conventional drive units.